Ed orally agrees with Far East Restaurant to provide delivery service to its customers for six months. This contract is enforceable by

The contract is enforceable by either party. First, all parties are in agreement. As what the sentence suggests, Far East Restaurant may have first asked Ed's services and offered perhaps, income or whatever in exchange of those services, which Ed agreed in return. Second, they both receive benefits. Ed receives revenues while Far East receives labor. Lastly, on the technicalities, most contracts can be either written or oral and still be legally enforceable.